WO2020138018A1

WO2020138018A1 - Mold, manufacturing device, and manufacturing method for manufacturing molded body

Info

Publication number: WO2020138018A1
Application number: PCT/JP2019/050459
Authority: WO
Inventors: 田中　亨; 佐藤　隆; 隼人加藤; 和仁小田根
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2018-12-28
Filing date: 2019-12-24
Publication date: 2020-07-02
Also published as: JPWO2020138018A1; CN113260472B; US20210283684A1; CN113260472A; JP7382605B2

Abstract

This mold comprises: a pair of first mold parts which respectively define a first surface and a second surface; a pair of second mold parts which respectively define a third surface and a fourth surface; and a pair of third mold parts which respectively define a fifth surface and a sixth surface. At least one of the third mold parts is provided with an upper mold part which defines a first-surface-side region of the fifth surface or the sixth surface and a lower mold part which defines a second-surface-side region of the fifth surface or the sixth surface and is slidable independently of the upper mold part. A step portion using the lower mold part can be formed by causing the lower mold part to protrude more toward a mold space than the upper mold part. The upper mold part can be moved forward relative to the lower mold part to make the step portion small. The upper mold part and the lower mold part can be integrally moved forward in the state where the step portion remains and the state where the step portion is absent.

Description

Mold for manufacturing molded body, manufacturing apparatus and manufacturing method

The present invention relates to a mold for manufacturing a molded body, a manufacturing apparatus, and a manufacturing method.

In recent years, as electronic devices have become smaller and lighter, small-sized and large-capacity high-frequency capacitors have been required. As such a capacitor, an electrolytic capacitor having a small equivalent series resistance (ESR) and excellent frequency characteristics is under development. As the anode body of the electrolytic capacitor, for example, a porous sintered body obtained by sintering valve action metal particles such as tantalum, niobium, and titanium is used.

The porous sintered body is usually manufactured by charging valve-acting metal particles into a space partially defined by a mold, press-molding the particles, and then sintering the particles. The valve action metal particles are usually introduced through an opening provided above the space. After the valve action metal particles are charged, the opening is closed by a mold holding the anode wire and pressure molding is performed. Thereby, a molded body in which the anode wire is erected from the upper surface is obtained. However, the density of the valve action metal particles on the surface where the anode wire is planted tends to be sparse, and the anode wire may not be sufficiently fixed in the molded body after pressure molding.
Therefore, Patent Document 1 proposes a method of increasing the density of the valve action metal particles on the surface side on which the anode wire is planted.

JP, 10-163074, A

In the method described in Patent Document 1, the density of the valve action metal particles on the surface side of the molded body may become excessively high. If the density of the valve action metal particles is too high, the particles are likely to be bonded to each other and the surface area of the molded product is reduced. In this case, the capacity of the electrolytic capacitor is reduced. In addition, the density difference of the molded body may become large between the surface side and the surface side opposite to the surface side. Then, cracks are likely to occur near the interface between the sparse region and the dense region of the molded body (or the sintered body), and the leakage current may increase when used as an electrolytic capacitor.

1st aspect of this invention is a metal mold|die which defines the molding space of a rectangular parallelepiped type|mold, The said rectangular parallelepiped has the 1st surface with which an anode wire can be planted, and the 2nd surface facing the said 1st surface. A third surface and a fourth surface which intersect the first surface and the second surface and are opposed to each other, and intersect the first surface, the second surface, the third surface and the fourth surface, And a fifth surface and a sixth surface facing each other, and the mold has a pair of first mold parts defining the first surface and the second surface, respectively, and the third surface and the third surface. At least one of the third mold parts has a pair of second mold parts that respectively define a fourth surface, and a pair of third mold parts that respectively define the fifth surface and the sixth surface. One defines an upper mold part that defines a region of the fifth surface or the sixth surface on the first surface side, and a region of the fifth surface or the sixth surface on the second surface side, And a lower mold part that is slidable independently of the upper mold part, and the lower mold part is projected toward the molding space side from the upper mold part to form the lower mold part. A step part can be formed by a mold part, and the upper mold part can be relatively advanced with respect to the lower mold part so as to reduce the step part, and the upper mold part and the The lower die part is a die that can be integrally advanced in a state where the step portion is maintained and a state where the step portion is not provided.

A second aspect of the present invention is an apparatus for manufacturing a molded body, which includes a mold and a hopper for charging metal particles into a space partially defined by the mold.

A third aspect of the present invention is a method for producing a molded body using the mold according to claim 1, wherein the first mold part on one side, the pair of second mold parts on the other side, The third mold part defines a first step of partially defining an initial space larger than the molding space, and a second step of introducing metal particles into the partially defined initial space. And a third step of advancing the third mold part in the initial space to press the metal particles. In the first step, the step part is formed by the lower mold part. In the third step, the step of integrally advancing the upper mold part and the lower mold part while maintaining the step portion, and the step of advancing the third mold part, A step of advancing the upper mold part relative to the lower mold part so as to reduce the step, and the step of forming the upper mold part and the lower mold part without the step. And a step of integrally advancing in a state.

A fourth aspect of the present invention is a method for producing a porous sintered body, which includes a step of firing the molded body obtained by the above production method.

In a fifth aspect of the present invention, a first surface, a second surface facing the first surface, a third surface and a fourth surface intersecting the first surface and the second surface and facing each other. And a porous sintered body having a fifth surface and a sixth surface which intersect the first surface, the second surface, the third surface and the fourth surface, and face each other, and the porous material. An anode wire, a part of which is embedded in the sintered body, the rest of which extends from the first surface, a dielectric layer formed on the porous sintered body, and a solid electrolyte layer formed on the dielectric layer. And a cathode layer formed on the solid electrolyte layer, wherein at least one of the fifth surface and the sixth surface extends in a direction intersecting the longitudinal direction of the anode wire. And the boundary line defines an upper mold part that defines a region of the fifth surface or the sixth surface on the first surface side, and a boundary of the upper surface of the fifth surface or the sixth surface on the second surface side. Originating from the boundary between the upper mold part and the lower mold part that is slidable independently of the upper mold part, and when viewed from the direction normal to the fifth surface or the sixth surface, The shortest length La in the longitudinal direction from the boundary line to the first surface and the shortest length Lb in the longitudinal direction from the boundary line to the second surface satisfy the relationship of La≦Lb, Regarding electrolytic capacitors.

A sixth aspect of the present invention is directed to a first surface, a second surface facing the first surface, a third surface and a fourth surface intersecting the first surface and the second surface and facing each other. And a porous sintered body having a fifth surface and a sixth surface which intersect the first surface, the second surface, the third surface and the fourth surface, and face each other, and the porous material. An anode wire, a part of which is embedded in the sintered body, the rest of which extends from the first surface, a dielectric layer formed on the porous sintered body, and a solid electrolyte layer formed on the dielectric layer. And a cathode layer formed on the solid electrolyte layer, wherein at least one of the fifth surface and the sixth surface extends in a direction intersecting the longitudinal direction of the anode wire. And the boundary line defines an upper mold part that defines a region of the fifth surface or the sixth surface on the first surface side, and a boundary of the upper surface of the fifth surface or the sixth surface on the second surface side. Originating from the boundary between the upper mold part and the lower mold part that is slidable independently of the upper mold part, and when viewed from the direction normal to the fifth surface or the sixth surface, An end portion of the anode wire embedded in the porous sintered body is related to the electrolytic capacitor, which is located in a portion from the boundary line of the porous sintered body to the second surface.

According to the present invention, a molded body having a small difference in density of metal particles can be obtained.

It is a development schematic diagram which looked at the metallic mold concerning one embodiment of the present invention from the upper part. It is a development schematic diagram which looked at the metallic mold concerning one embodiment of the present invention from the side. 6 is a flowchart showing a manufacturing method according to an embodiment of the present invention. It is sectional drawing which shows typically arrangement|positioning of the metal mold|die in the 1st process of the manufacturing method which concerns on one Embodiment of this invention. It is sectional drawing which shows typically arrangement|positioning of the metal mold|die in the 2nd process of the manufacturing method which concerns on one Embodiment of this invention. It is sectional drawing which shows typically the initial arrangement|positioning of the 3rd metal mold components in the 3rd process of the manufacturing method which concerns on one Embodiment of this invention. FIG. 9 is a cross-sectional view schematically showing how the upper mold component and the lower mold component have integrally advanced while maintaining a step in the third step of the manufacturing method according to the embodiment of the present invention. FIG. 9 is a cross-sectional view schematically showing how the upper die part relatively advances in the third step of the manufacturing method according to the embodiment of the present invention. In the 3rd process of the manufacturing method which concerns on one Embodiment of this invention, the mode that the surface of the upper mold part of the upper space side and the surface of the lower mold part of the lower space side became flush is shown typically. FIG. FIG. 9 is a cross-sectional view schematically showing a state in which an upper mold component and a lower mold component are arranged at predetermined positions defining a molding space in the third step of the manufacturing method according to the embodiment of the present invention. It is sectional drawing which shows typically the initial state of the operation part of the 3rd metal mold|die part which concerns on one Embodiment of this invention. It is sectional drawing which shows typically the state at the time of the completion|finish of operation|movement of the operation part of the 3rd metal mold|die part which concerns on one Embodiment of this invention. It is a sectional view showing typically an electrolytic capacitor using a porous calcination object concerning one embodiment of the present invention. It is a perspective view which shows typically the molded object with which the anode wire which concerns on one Embodiment of this invention was embedded. It is a perspective view which shows typically the porous sintered compact for demonstrating the evaluation method in an Example.

In this embodiment, the density difference of the metal particles is reduced by providing a sufficient space in which the metal particles can move at the start of pressure molding. Specifically, in the mold according to the present embodiment, the third mold part defining the fifth surface or the sixth surface intersecting the first surface on which the anode wire is erected can be slid independently. Into upper mold part and lower mold part. Then, by projecting the lower mold component toward the molding space, a step portion is formed in the molding space by the lower mold component. With this step, in the initial space where pressure molding is started, the upper space formed by the upper mold part, the first mold part defining the first surface, and the pair of second mold parts, A lower space formed by the lower mold part, the first mold part defining the second surface, and the pair of second mold parts is formed.

The width of the upper space in the sliding direction A is larger than the width of the lower space in the sliding direction A. In this state, by advancing the entire third mold component, the charged metal particles can easily move from the lower space to the upper space. Therefore, the density of the metal particles in the lower space is suppressed from becoming excessively high, and the density of the metal particles in the upper space is increased. That is, the difference in density of metal particles between the upper space and the lower space becomes small.

<Mold>
The mold according to this embodiment is used to mold a molded body on which the anode wire is erected. The molded body has a substantially rectangular parallelepiped shape, and the anode wire is erected from one surface thereof.

The molded body has a first surface on which the anode wire can be erected, a second surface facing the first surface, and a third surface and a fourth surface intersecting the first surface and the second surface and facing each other. , A first surface, a second surface, a third surface, and a fourth surface, and a fifth surface and a sixth surface which face each other. The third surface and the fourth surface may be narrower than the fifth surface and the sixth surface.

The metal mold defines a rectangular parallelepiped mold space corresponding to the above-mentioned molded body. The molding space also has a first surface corresponding to the molded body, a second surface facing the first surface, a third surface and a fourth surface intersecting the first surface and the second surface, and facing each other, A fifth surface and a sixth surface which intersect the first surface, the second surface, the third surface and the fourth surface, and which face each other.

The mold includes a pair of first mold parts, a pair of second mold parts, and a pair of third mold parts.
The pair of first mold parts define a first surface and a second surface of the molding space. One first mold part may carry the anode wire. The pair of first mold parts are arranged so as to face each other and are slidable in the longitudinal direction of the anode wire.

The pair of second mold parts define the third surface and the fourth surface of the molding space. The pair of second mold parts are arranged so as to face each other, and are slidable in a direction toward and away from each other.

The pair of third mold parts define the fifth surface and the sixth surface of the molding space. The pair of third mold components are arranged so as to face each other, and are slidable in a direction toward each other and a direction away from each other (hereinafter, may be collectively referred to as a sliding direction A). The sliding of the third mold component in the direction of reducing the space defined by itself is referred to as advancing. The sliding of the third mold component in the direction of enlarging the space defined by itself is referred to as retreating.

At least one of the third mold parts defines an upper mold part that defines a first surface side of the fifth surface or the sixth surface and a second surface side area of the fifth surface or the sixth surface. And a lower mold part. The upper mold part and the lower mold part can slide independently. At the initial position where the pressure molding is started, the lower mold component projects toward the molding space side from the upper mold component. Therefore, at the start of pressure molding, the third mold component has a stepped portion formed by the lower mold component, and the initial space has a lower space partially defined by the lower mold component, A part thereof is defined by the upper mold part, and an upper space having a large width in the sliding direction A is formed.

At the start of pressure molding, at least a part of the lower space is filled with metal particles. Part of the head space may also be occupied by metal particles. When the pair of third mold parts approach each other, the metal particles filled in the lower space move from the narrowed lower space to the upper space having a wide space not filled with metal particles. Since the width of the upper space in the sliding direction A is wider than the width of the lower space in the sliding direction A, the metal particles can be easily moved to the upper space.

The length (width Wa) of the step in the sliding direction A is not particularly limited, but is, for example, 2% or more of the length (width W40) of the molding space in the sliding direction A. When the ratio of the width Wa to the width W40 is in this range, the density on the first surface side of the molded body tends to be high. The ratio of the width Wa to the width W40 may be 3% or more. The width Wa of the step is preferably not excessively large in that the difference in density of the metal particles between the upper space and the lower space becomes small. The width Wa of the stepped portion is, for example, 15% or less of the width W40 of the molding space. When the ratio of the width Wa to the width W40 is in this range, excessive movement of the metal particles to the upper space is suppressed, and the density of the obtained molded body on the first surface side and the density on the second surface side are uniform. It is easy to become. The ratio of the width Wa to the width W40 may be 10% or less, and may be 8% or less. The width W40 of the molding space is synonymous with the distance W between the fifth surface and the sixth surface of the molded body.

The ratio of the length of the upper mold part and the lower mold part in the direction perpendicular to the sliding direction A is not particularly limited. Ratio (Ha:Hb) of the length (height Ha) of the upper die part in the direction perpendicular to the sliding direction A and the length (height Hb) of the lower die part in the direction perpendicular to the sliding direction A May be, for example, 4:1 to 1:4 and may be 2:3 to 1:3. The height Hb is preferably equal to or higher than the height Ha in that the difference in the density of the metal particles between the upper space and the lower space tends to be small. Ha:Hb may be, for example, 1:1 to 1:4 and may be 1:1 to 1:3.

The initial minimum distance W0 between the pair of third mold parts in the sliding direction A is not particularly limited as long as it is larger than the width W40 of the molding space. The initial distance W0 may be, for example, larger than 100% of the width W40 of the molding space, 300% or more, or 500% or more. The initial interval W0 may be 1000% or less of the width W40 of the molding space, and may be 800% or less. When both the pair of third mold parts include the upper mold part and the lower mold part, the initial interval W0 can be referred to as an initial interval W0 between the lower mold parts.

When the pressure molding is started, the upper mold part and the lower mold part integrally move forward while maintaining the step. The upper mold part then advances relative to the lower mold part, the step becomes smaller and eventually the step disappears. After that, the upper mold part and the lower mold part are integrally advanced to a predetermined position without any step.

FIG. 1A is a development schematic view of the mold according to the present embodiment as seen from above. In FIG. 1A, the first mold part is omitted for convenience. FIG. 1B is a development schematic view of the mold according to the present embodiment as viewed from the side. In FIG. 1B, the second mold part is omitted for convenience. Further, in FIG. 1B, the pair of third mold parts are divided into the upper mold part and the lower mold part, respectively, but the invention is not limited to this. It is sufficient that one of the pair of third mold components includes the upper mold component and the lower mold component. The third mold component may further include a mold component on the side opposite to the lower mold component of the upper mold component.

The mold 30 defines a pair of first mold parts (31A and 31B) that define a first surface 40a and a second surface 40b of the molding space 40, and a third surface 40c and a fourth surface 40d of the molding space 40. A pair of second mold parts (32A and 32B) and a pair of third mold parts (33A and 33B) defining the fifth surface 40e and the sixth surface 40f of the molding space 40.

The pair of

first mold parts

31A and 31B are arranged so as to face each other and are slidable in the longitudinal direction of the anode wire 2. The pair of

second mold parts

32A and 32B are arranged so as to face each other, and are slidable in a direction toward and away from each other. The pair of

third mold parts

33A and 33B are also arranged so as to face each other and are slidable in a direction toward and away from each other.

The

third mold components

33A and 33B each include an upper mold component 331 and a lower mold component 332. The upper mold part 331 and the lower mold part 332 can slide independently. In the initial position where pressure molding is started, the

third mold parts

33A and 33B have a step 332a formed by the lower mold part 332. The upper die part 331 and the lower die part 332 can be integrally advanced while maintaining the step 332a. Upper mold part 33
1 can be moved forward relative to the lower mold part 332 so as to make the step 332a smaller. The upper die part 331 and the lower die part 332 can be integrally advanced even without the step 332a.

<Molded body manufacturing equipment>
The apparatus for manufacturing a molded body according to the present embodiment includes the above-mentioned mold and a hopper (not shown) for charging metal particles into the space partially defined by the mold. The hopper is defined by, for example, one first mold part that does not hold the anode wire, a pair of second mold parts, and a pair of third mold parts, and is defined in a predetermined space larger than the molding space. Charge metal particles in mass.

<Molded body manufacturing method>
The molded body according to the present embodiment partially defines an initial space larger than the molding space by the one first mold component, the pair of second mold components, and the pair of third mold components. One step (S1), a second step (S2) of injecting metal particles into the partially defined initial space, and a third mold part are advanced in the defined initial space to remove the metal particles. It is manufactured by a method including a third step (S3) of pressing.
FIG. 2 is a flowchart showing the manufacturing method according to the present embodiment.

(1) First step A first mold part that does not hold an anode wire, a pair of second mold parts, and a pair of third mold parts partially define an initial space that is larger than the molding space. ..

The placement of the pair of third mold parts is tentative. In the steps after the second step, the third mold part is further slid. The arrangement of the first mold part and the second mold part may be provisional. For example, in a step after the second step, the first mold part and the second mold part may also be slid further.

FIG. 3 is a sectional view schematically showing the arrangement of the molds in the first step. In FIG. 3, one second mold component is omitted for convenience. Further, in FIG. 3, the pair of third mold parts are divided into the upper mold part and the lower mold part, but the invention is not limited to this.

The lower mold part 332 projects to the initial space S0 side from the upper mold part 331, and a step part 332a is formed by the lower mold part 332. The width Wa of the step 332a is 3% or more and 8% or less of the width W40 (see FIG. 1B) of the molding space. The ratio (Ha:Hb) between the height Ha of the upper die part and the height Hb of the lower die part is 1:2. The initial minimum distance W0 in the sliding direction A between the third mold component 33A and the third mold component 33B is, for example, 500% or more and 800% or less of the width W40 of the molding space.

An initial space S0 larger than the molding space 40 is partially defined by the first mold part 31B that does not hold the anode wire 2, the pair of second mold parts 32A, and the pair of

third mold parts

33A and 33B. ing. The initial space S0 is an upper space Sa formed by an upper mold part 331, a first mold part 31A defining the first surface 40a, and a pair of second mold parts 32A, a lower mold part 332, and a lower mold part 332. It has a lower space Sb formed by a first mold part 31B defining a second surface 40b and a pair of second mold parts 32A. The width of the upper space Sa in the sliding direction A is larger than the width of the lower space Sb in the sliding direction A by about twice the width Wa of the step portion 332a.

(2) Second step Metal particles having a predetermined mass are put into the partially defined initial space.
The initial space is wide enough for the metal particles to be charged. Therefore, even after the metal particles are charged, at least a part of the upper space is not filled with the metal particles and is maintained.

FIG. 4 is a sectional view schematically showing the arrangement of molds in the second step. In FIG. 4, one of the second mold parts is omitted for convenience. The metal particles 1P put in the initial space S0 spread in a pyramid shape as shown in the illustrated example. Therefore, the upper space and a part of the lower space are maintained without being filled with the metal particles 1P.

(3) Third Step For example, the first mold part is slid to a predetermined position to define the initial space. The third mold part is advanced within the defined initial space. As a result, the metal particles are pressed and the molded body is molded.

Before sliding the third mold part, the second mold part may be further slid to a predetermined position. The pair of third mold parts may be slid at the same time, or one of the third mold parts may be fixed and only the other third mold part may be slid.

The third step is a step (S31) of integrally advancing the upper die part and the lower die part in a state where the step part is maintained, and the upper die part is moved downward so as to make the step part smaller. The method includes a step (S32) of advancing relative to the die part, and a step (S33) of advancing the upper die part and the lower die part integrally without a step.

　The upper space is wider in the sliding direction A than the lower space. Thus, when the upper and lower mold components are integrally advanced while maintaining the stepped portion, the charged metal particles can easily move from the lower space to the upper space. Therefore, the density of the metal particles in the lower space is suppressed from becoming excessively high, and the density of the metal particles in the upper space is increased. That is, the density difference between the upper space and the lower space becomes small.

When the distance between the pair of third mold parts is narrowed to a certain extent, the density of the metal particles charged in the lower space increases, and a force for pushing the lower mold parts backward is generated. On the other hand, the pushing force in the backward direction is less likely to be applied to the upper mold component, which is arranged at a distance from the lower mold component. Therefore, the upper mold part advances relative to the lower mold part, and the step becomes smaller. When the step portion disappears and the surface of the upper mold part on the upper space side and the surface of the lower mold part on the lower space side become flush with each other, the relative advance of the upper mold part stops, and the upper mold part stops. The lower die part and the lower die part are integrally advanced without a step.

5A to 5E are schematic cross-sectional views showing the operation of the third mold part in the third step. In FIGS. 5A to 5E, the second mold part is omitted for convenience.

FIG. 5A is a sectional view schematically showing an initial arrangement of the third mold component.
In FIG. 5A, before sliding the

third mold parts

33A and 33B, the

first mold parts

31A and 31B are slid to predetermined positions to define the entire initial space S0. Further, the

second mold parts

32A and 32B are slid to predetermined positions that define a part of the molding space 40. Thereby, a part of the molding space 40 is also defined. After that, the first mold part and the second mold part do not have to slide. The minimum initial distance in the sliding direction A between the third mold part 33A and the third mold part 33B is W0.

FIG. 5B is a cross-sectional view schematically showing a state where the upper mold component and the lower mold component have integrally advanced while maintaining a step.
The minimum first distance W1 in the sliding direction A between the third mold parts is smaller than the initial distance W0. The upper mold part and the lower mold part are integrally advanced, and the upper space and the lower space are both narrow. However, since the metal particles 1P can escape to the wider upper space in the sliding direction A, the density of the metal particles in the lower space does not rise excessively. On the other hand, the density of metal particles in the upper space increases.

FIG. 5C is a cross-sectional view schematically showing how the upper mold part relatively advances.
When the second distance W2 in the sliding direction A between the lower mold components 332 becomes smaller than the first distance W1, both the upper space and the lower space are filled with metal particles. Then, the density of the metal particles 1P in the lower space, which is a narrower space, becomes higher than that in the upper space, and the lower mold component 332 is pushed in the backward direction. Therefore, the width Wa1 of the step portion 332a is smaller than the initial width Wa. However, the entire third mold component slides in the forward direction.

FIG. 5D is a cross-sectional view schematically showing a state in which the upper space side surface of the upper mold component and the lower space side surface of the lower mold component are flush with each other.
The width Wa of the step 332a gradually decreases, and finally the step 332a disappears (Wa=0). Then, the relative advance of the upper mold part 331 is stopped, and the upper mold part 331 and the lower mold part 332 are integrally advanced. The third interval W3 between the third mold parts when the relative advance of the upper mold part 331 is stopped is smaller than the second interval W2.

FIG. 5E is a cross-sectional view schematically showing a state where the upper mold component and the lower mold component are arranged at predetermined positions that define the molding space.
The upper mold part 331 and the lower mold part 332 are integrally advanced to a predetermined position. The predetermined position is a position where the distance between the third mold components is the width W40 of the molding space. The upper die part 331 and the lower die part 332 integrally move forward and compress the metal particles until the distance between the third die parts changes from W3 to W40.

After the step due to the lower mold part disappears, the upper mold part and the lower mold part move forward integrally and compress the metal particles, eliminating the pressure difference between the upper space and the lower space. To be done. Furthermore, since the metal particles in the upper space and the lower space that have not been compressed are compressed at the same timing, it is difficult for the boundary between the upper space and the lower space to occur. Therefore, when the molded body of the present embodiment is used for an electrolytic capacitor, leakage current is easily suppressed.

The operation of the upper mold part and the lower mold part in the third step can be realized by the operation unit having the following mechanism.

The operating portion of the third mold component includes a rod-shaped member (hereinafter referred to as a pin) extending in the sliding direction A of the third mold component, a ring-shaped spacer, a biasing member, and a base body.
One end (first end) of the pin is in contact with a part of the lower mold part from the opposite side of the molding space. The other end (second end) of the pin extends toward the base. A collar is provided in the middle of the pin. The spacer is inserted on the side of the second end of the collar provided on the pin. The thickness of the spacer determines the width Wa of the step. The biasing member is arranged between the base body and the spacer and is in contact with each of them. The biasing member is, for example, an elastic body such as a spring.

When the biasing member is in an unloaded state, the second end of the pin is not in contact with the base, and a gap having the same width as the spacer is formed between the second end of the pin and the base. There is. When the pin is pushed by the lower mold part, the gap between the pin and the base becomes smaller and eventually the second end abuts the base. As a result, the retreat of the lower die part (the relative advance of the upper die part) is stopped. When the second end of the pin contacts the base, the surface of the upper mold part on the upper space side is flush with the surface of the lower mold part on the lower space side.

The lower mold part slides as the pin slides. On the other hand, the upper mold part is in contact with the base body and is independent of the pins. In the initial state, the biasing member is not loaded and a gap is formed between the second end of the pin and the base body. Therefore, the lower mold component projects toward the lower space side by the amount of the spacer than the upper mold component. As a result, a step is formed by the lower die part. The step portion has the same width as the thickness of the spacer.

When the distance between the pair of third mold parts becomes narrower to some extent and the density of metal particles in the lower space increases, the lower mold part is pushed in the backward direction and the upper mold part relatively moves forward. Therefore, the pin is also pushed toward the base body, and the flange of the pin pushes the biasing member against the base body through the spacer. On the other hand, the biasing member tries to push the pin back to the lower space side. By adjusting the urging force of the urging member, the pressure applied to the metal particles can be controlled. The relative advancement of the upper mold part ends when the second end of the pin reaches the base body.

However, in the third step, the sliding control part of the third mold part including the above-mentioned operating part advances the third mold part. For example, the slide control unit advances the entire third mold component by moving the base body to the molding space side. That is, while the upper die part is relatively advanced with respect to the lower die part, the entire third die part is also advanced, and the space becomes narrower over time. Even after the second end of the pin reaches the base body, the upper die part and the lower die part are integrally advanced.

FIG. 6A is a cross-sectional view schematically showing the initial state of the operation part of the third mold component. Although FIG. 6A shows the case where the operation unit 50 regulates the operation of the third mold component 33A, the present invention is not limited to this.

The operating unit 50 includes a pin 51 extending in the sliding direction A of the third mold component 33A, a biasing member 52, a ring-shaped first spacer 53A, and a base 54. A collar 51 a is provided in the middle of the pin 51. The first spacer 53A is inserted on the second end side of the flange 51a. The second spacer 53B may be inserted on the first end side of the flange 51a. The biasing member 52 is, for example, a coil spring, is arranged between the base 54 and the first spacer 53A, and is in contact with each of them.

The first end of the pin 51 is in contact with a part of the lower mold part 332 from the opposite side of the molding space. The second end of the pin 51 is not in contact with the base 54 when the biasing member 52 is in an unloaded state, and a gap G having the same width as the thickness of the first spacer 53A is formed between the second end of the pin 51 and the base 54. Has been done. The width of the gap G (the length in the sliding direction A) is the same as the width Wa of the step portion 332a formed in the third mold component 33A.

FIG. 6B is a sectional view schematically showing a state at the end of the operation of the operation unit of the third mold component.
When the lower die part 332 is pushed in the backward direction, the biasing member 52 contracts and the gap G between the pin 51 and the base 54 becomes smaller. The retreat of the lower mold part 332 (the relative advance of the upper mold part 331) ends when the second end of the pin 51 abuts the base 54. When the second end of the pin 51 and the base 54 contact each other, the upper space side surface of the upper mold part 331 and the lower space side surface of the lower mold part 332 are flush with each other.

<Method for producing porous sintered body>
(4) Fourth Step After the mold is completely removed, the molded body may be fired. Thereby, a porous sintered body is obtained. The firing is performed in vacuum, for example. The firing temperature and time are not particularly limited and may be appropriately set depending on the material of the metal particles and the like.

<Molded body and porous sintered body>
The molded body (and the porous sintered body that is a fired product thereof) includes an anode wire, a first surface on which the anode wire is erected, a second surface facing the first surface, a first surface and a second surface. A third surface and a fourth surface which intersect the two surfaces and face each other, and a fifth surface and a sixth surface which intersect the first surface, the second surface, the third surface and the fourth surface, and face each other. With.

When the third mold part that defines the fifth surface or the sixth surface is constituted by the upper mold part and the lower mold part that are independently slidable as in the present embodiment, A boundary line extending in a direction intersecting the longitudinal direction of the anode wire is formed on at least one surface of the sixth surface. This boundary line originates from the boundary between the upper mold part and the lower mold part. When viewed from the normal direction of the fifth surface or the sixth surface, the portion on the first surface side from the boundary line of the molded body is formed by pressure-molding the metal particles with which the upper space is filled. Similarly, the portion on the second surface side from the boundary line of the molded body is formed by pressure-molding the metal particles with which the lower space is filled.

When viewed from the normal direction of the fifth surface or the sixth surface, the shortest length La in the longitudinal direction of the anode wire from the boundary line to the first surface and the longitudinal direction of the anode wire from the boundary line to the second surface The ratio to the shortest length Lb is not particularly limited, and depends on the ratio of the height Ha of the upper die part to the height Hb of the lower die part. The ratio of the length La to the length Lb (La:Lb) may be, for example, 4:1 to 1:4 or 2:3 to 1:3. The length Lb is preferably equal to or greater than the length La in that the anode wire is more easily fixed. La:Lb may be, for example, 1:1 to 1:4 and may be 1:1 to 1:3.

When viewed in the normal direction of the fifth surface or the sixth surface, the end portion of the anode wire that is embedded in the molded body may be on the second surface side from the boundary line. At this time, the shortest distance H2a from the end of the anode wire to the second surface is shorter than the length La (H2a<Lb). This makes it easier for the anode wire to be more firmly fixed. The shortest distance H2a may be 1/3 or less of the sum of the length La and the length Lb, and may be 1/4 or less. From the viewpoint of the fixability of the anode wire, it is preferable that the length Lb is equal to or greater than the length La and that the end portion of the anode wire is located on the second surface side from the boundary line.

FIG. 8 is a perspective view schematically showing a molded body in which a part of the anode wire according to the embodiment is embedded.
The molded body 1 (and the porous sintered body 1X which is a fired product thereof) has a first surface 1a and a second surface 1b, a third surface 1c and a fourth surface 1d, a fifth surface 1e and a sixth surface. 1f and. The third surface 1c and the fourth surface 1d are smaller than the fifth surface 1e and the sixth surface 1f. The molded body 1 is flat and has, for example, a flat plate shape. A part of the anode wire 2 is embedded in the molded body 1, and the remaining part extends from the first surface 1 a of the molded body 1 to the outside.

A boundary line B extending in a direction intersecting the longitudinal direction of the anode wire 2 is formed on the fifth surface 1e and the sixth surface 1f of the molded body 1. When viewed from the normal direction of the fifth surface 1e or the sixth surface 1f, the length Lb from the boundary line B to the second surface 1b is longer than the length La from the boundary line B to the first surface 1a (Lb> La). The end 2a of the anode wire 2 which is embedded in the molded body 1 is located on the second surface 1b side from the boundary line B. The shortest distance H2a from the end 2a to the second surface 1b is shorter than the length La (H2a<Lb).

<Electrolytic capacitor>
The porous sintered body obtained according to this embodiment is used, for example, in a capacitor element that constitutes an electrolytic capacitor.
FIG. 7 is a sectional view schematically showing an electrolytic capacitor using the porous sintered body according to this embodiment.

The electrolytic capacitor 20 has a substantially hexahedral outer shape including three sets of opposed flat surfaces, and has a capacitor element 10, a resin outer package 11 that seals the capacitor element 10, and an anode exposed to the outside of the resin outer package 11. A terminal 7 and a cathode terminal 9 are provided.

The capacitor element 10 includes a porous sintered body 1X as an anode body in which a part of an anode wire 2 electrically connected to an anode terminal 7 is embedded, a dielectric layer 3 formed on the surface thereof, It has a solid electrolyte layer 4 formed on the surface of the dielectric layer 3 and a cathode layer 5 formed on the surface of the solid electrolyte layer 4.

The porous sintered body 1X is obtained by press-molding valve-acting metal particles such as tantalum, niobium, titanium, or alloys thereof and firing them, but the present invention is limited to these metal particles. is not.

A part of the anode wire 2 protruding from the porous sintered body 1X is electrically connected to the anode terminal 7 by resistance welding or the like. On the other hand, the cathode layer 5 is electrically connected to the cathode terminal 9 in the resin outer package 11 via the conductive adhesive 8 (for example, a mixture of thermosetting resin and metal particles). The anode terminal 7 and the cathode terminal 9 shown in FIG. 8 are bent so that they protrude from the resin outer package 11 and the lower surface thereof is disposed on the same plane as the bottom surface of the resin outer package 11. The lower surfaces of the anode terminal 7 and the cathode terminal 9 are used for solder connection with a substrate (not shown) on which the electrolytic capacitor 20 is to be mounted.

(Dielectric layer)
The dielectric layer can be formed as an oxide film by oxidizing the surface of the conductive material forming the porous sintered body. Specifically, the porous sintered body is immersed in a chemical conversion tank filled with an electrolytic aqueous solution (for example, phosphoric acid aqueous solution), and the protruding anode wire is connected to the porous sintered body to perform anodization. As a result, a dielectric layer made of an oxide film of a valve metal can be formed on the surface of the porous sintered body. The electrolytic aqueous solution is not limited to the phosphoric acid aqueous solution, and nitric acid, acetic acid, sulfuric acid, or the like can be used.

(Solid electrolyte layer)
The solid electrolyte layer is formed so as to cover the dielectric layer. The solid electrolyte layer is made of, for example, manganese dioxide, a conductive polymer, or the like. The solid electrolyte layer containing a conductive polymer is obtained by, for example, impregnating a porous sintered body on which a dielectric layer is formed with a monomer or oligomer, and then polymerizing the monomer or oligomer by chemical polymerization or electrolytic polymerization. Alternatively, the porous sintered body on which the dielectric layer is formed is impregnated with a solution or dispersion liquid of a conductive polymer and dried to form on the dielectric layer.

In the step of forming the dielectric layer and the solid electrolyte layer, for example, a part of the anode wire protruding from the porous sintered body is grasped and the porous sintered body is suspended, and then the porous sintered body is suspended. In some cases, a dielectric layer is formed on top of the dielectric layer, and a solid electrolyte layer is further formed thereon. Therefore, a large load is applied near the base of the anode wire. If the fixing of the anode wire is not sufficient, cracks are likely to occur in the porous sintered body from the vicinity of the root of the anode wire, and the leakage current tends to increase. According to this embodiment, since the anode wire is firmly fixed, the occurrence of cracks is also suppressed.

(Cathode layer)
The cathode layer has, for example, a carbon layer formed so as to cover the solid electrolyte layer, and a metal paste layer formed on the surface of the carbon layer. The carbon layer contains a conductive carbon material such as graphite and a resin. The metal paste layer contains, for example, metal particles (for example, silver) and a resin. Note that the structure of the cathode layer is not limited to this structure. The cathode layer may have any structure as long as it has a current collecting function.

Hereinafter, the present invention will be specifically described based on Examples, but the present invention is not limited to the following Examples.
[Example 1]
Using the mold shown in FIGS. 1A and 1B, tantalum particles are pressure-molded to obtain a molded body x shown in FIG. 8 having a width W of 0.83 mm and a length in the direction perpendicular to the width W of 5.17 mm. It was made. The operation of the pair of third mold parts was controlled by the operation unit shown in FIG. 6A. The initial minimum distance W0 between the third mold parts was 5 mm. The width Wa of the step is 0.05 mm. The ratio Ha/Hb of the height Ha of the upper die part to the height Hb of the lower die part was about 1/2. The obtained molded body x was fired to produce five porous sintered bodies A1.

[Comparative Example 1]
Five porous sintered bodies B were produced in the same manner as in Example 1 except that the third mold component that was not vertically divided was used.

[Evaluation]
The following evaluations were performed on the porous sintered bodies A1 and B.

(1) Fracture strength Three straight lines are drawn on the fourth surface of the porous sintered body in the longitudinal direction of the anode wire, a point P1 on the straight line Lc at the center thereof, which is 0.5 mm away from the first surface, and The breaking strength was measured at the point P2 on the central straight line Lc and 0.5 mm away from the second surface (see FIG. 9). The straight line Lc at the center divides the width of the fourth surface perpendicular to the longitudinal direction into two equal parts. Two straight lines L1 and L2 were drawn so as to sandwich the central straight line Lc at a position apart from the central straight line Lc by about 0.25 mm.

Rupture strength was measured by pressing the compression terminal against the porous sintered body using a tensile compression tester while applying a load. When the porous sintered body is broken, the load applied to the compression terminal is the breaking strength. The breaking strength (%) at the point P1 when the breaking strength at the point P2 was 100% was calculated. The breaking strength (%) was the average value of the five porous sintered bodies. The results are shown in Table 1.

In the porous sintered body A1, the breaking strength on the first surface side (point P1) where the anode wire extends is slightly larger than the breaking strength on the opposite second surface side (point P2). Therefore, the anode wire is firmly fixed. However, the breaking strength at the point P1 is not excessively large as compared with the point P2, and it can be said that the density is substantially uniform between the first surface side and the second surface side. On the other hand, in the porous sintered body B, the breaking strength on the first surface side (point P1) from which the anode wire extends is smaller than the breaking strength on the opposite second surface side (point P2). Further, there is a relatively large difference between the breaking strength at the point P1 and the breaking strength at the point P2.

(2) Vickers Hardness The straight lines Lc, L1 and L2 were drawn on the fourth surface of the porous sintered body, and 12 straight lines M1 to M12 were drawn in a direction perpendicular to the longitudinal direction of the anode wire. The straight line M1 closest to the first surface was drawn 0.25 mm away from the end of the fourth surface on the first surface side. Similarly, the straight line M12 closest to the second surface was also drawn at a position 0.25 mm away from the end of the fourth surface on the second surface side. The remaining 10 straight lines were drawn so as to divide the straight lines M1 and M2 into 11 equal parts. Vickers hardness was measured at 36 intersections of the straight lines Lc, L1 and L2 and the straight lines M1 to M12 (see FIG. 9). The Vickers hardness was measured according to JIS Z 2244.

Average values of Vickers hardness (Vickers hardness HVa) at 9 intersections of the straight lines Lc, L1 and L2 and the straight lines M1 to M3, and Vickers at 21 intersections of the straight lines Lc, L1 and L2 and the straight lines M6 to M12 The average value of hardness (Vickers hardness HVb) was calculated, and Vickers hardness HVa (%) was calculated when Vickers hardness HVb was 100%. The results are shown in Table 2. The Vickers hardness HVa and the Vickers hardness HVb were the average values of the five porous sintered bodies.

Regarding Vickers hardness, the same tendency as breaking strength was observed. That is, in the porous sintered body A1, the Vickers hardness on the first surface side from which the anode wire extends is slightly larger than the Vickers hardness on the opposite second surface side, but is not excessively large.

In the porous sintered body A1, the area from the end of the fourth surface on the first surface side to the straight line M3 corresponds to the portion pressed by the upper die part. In the porous sintered body A1, the area from the end on the second surface side of the fourth surface to the straight line M6 corresponds to the portion pressed by the lower die part. Since no large difference was found between the Vickers hardness HVa and the Vickers hardness HVb, it can be seen that the effect of dividing the third mold part is not so great.

[Examples 2 to 4]
Porous sintered bodies A2 to A4 were produced in the same manner as in Example 1 except that the width Wa of the step portion was set to 0.14 mm, 0.3 mm, and 0.5 mm. When the fracture strengths of the obtained porous sintered bodies A2 to A4 were measured in the same manner as above, the fracture strength at the point P1 increased as the width Wa increased, and the fracture strength at the width Wa and the point P1 It can be seen that there is a correlation between the two.

From the evaluation results of the porous sintered bodies A2 to A4 and the porous sintered body B, it was found that the first mold side of the porous sintered body was broken due to the fact that even a slight step portion was formed in the third mold component. It can be seen that the strength can be increased.

The present invention can be used for an electrolytic capacitor having a porous sintered body as an anode body.

10: Capacitor element 1: Molded body 1X: Porous sintered body 1P: Metal particle 1a: First surface 1b: Second surface 1c: Third surface 1d: Fourth surface 1e: Fifth surface 1f: Sixth surface 2 : Anode wire 2a: End part 3: Dielectric layer 4: Solid electrolyte layer 5: Cathode layer 7: Anode terminal 8: Conductive adhesive 9: Cathode terminal 11: Resin exterior body 20: Electrolytic capacitor 30: Mold 31A, 31B:

First mold part

32A, 32B:

Second mold part

33A, 33B: Third mold part 331: Upper mold part 332: Lower mold part 332a: Step part 40: Molding space 40a: First surface 40b: 2nd surface 40c: 3rd surface 40d: 4th surface 40e: 5th surface 40f: 6th surface 50: Operating part 51: Pin 51a: Tsuba 52: Energizing member 53A: 1st spacer 53B: 2nd spacer 54: substrate

Claims

A mold for defining a rectangular parallelepiped molding space,
The rectangular parallelepiped is
A first surface on which the anode wire can be erected;
A second surface facing the first surface;
A third surface and a fourth surface which intersect the first surface and the second surface and face each other;
A fifth surface and a sixth surface which intersect the first surface, the second surface, the third surface and the fourth surface, and which face each other,
The mold is
A pair of first mold parts that respectively define the first surface and the second surface;
A pair of second mold parts that respectively define the third surface and the fourth surface;
A pair of third mold parts that respectively define the fifth surface and the sixth surface,
At least one of the third mold components includes an upper mold component that defines a region of the fifth surface or the sixth surface on the side of the first surface, and the second mold component of the fifth surface or the sixth surface. A lower mold part that defines a surface side region and is slidable independently of the upper mold part,
By projecting the lower mold component toward the molding space side from the upper mold component, a step portion can be formed by the lower mold component,
The upper mold part is relatively advanceable with respect to the lower mold part so as to reduce the step portion,
A mold in which the upper mold part and the lower mold part can integrally advance in a state in which the step portion is maintained and a state in which the step portion is not provided.
The mold according to claim 1, wherein a length of the step portion in the sliding direction of the lower mold component is 2% or more and 15% or less of a length of the molding space in the sliding direction.
The mold according to claim 1 or 2, wherein the fifth surface and the sixth surface are larger than the third surface and the fourth surface.
The mold includes an operation unit that controls operations of the upper mold component and the lower mold component,
The operating unit includes a rod-shaped member extending in the sliding direction of the lower mold component, a spacer, a biasing member, and a base body,
The rod-shaped member includes a collar,
One end of the rod-shaped member is in contact with a part of the lower mold component from the opposite side of the molding space,
The other end of the rod-shaped member extends toward the base body,
The spacer is arranged between the collar and the base,
The biasing member is arranged between the base body and the spacer so as to abut the base body and the spacer,
When the urging member is in an unloaded state, a gap having the same width as the thickness of the spacer in the sliding direction of the lower mold component is formed between the rod-shaped member and the base body, so that the lower metal mold is formed. The step portion is formed by a mold part,
The mold according to any one of claims 1 to 3, wherein a length in the sliding direction of the lower mold component of the step portion decreases due to a load generated in a direction of contracting the biasing member.
A mold according to any one of claims 1 to 4,
An apparatus for manufacturing a molded body, comprising: a hopper for charging metal particles into a space partially defined by the mold.
A method for producing a molded body using the mold according to claim 1,
A first step of partially demarcating an initial space larger than the molding space by one of the first mold parts, a pair of the second mold parts, and a pair of the third mold parts;
A second step of introducing metal particles into the partially defined initial space;
A third step of advancing the third mold part in the defined initial space to press the metal particles,
In the first step, the step is formed by the lower mold part,
In the third step,
A step of integrally advancing the upper mold part and the lower mold part while maintaining the step portion;
Advancing the third mold part while advancing the upper mold part relative to the lower mold part so as to reduce the step portion;
A step of integrally advancing the upper mold part and the lower mold part without the step portion, the method for manufacturing a molded body.
A method for manufacturing a porous sintered body, comprising a step of firing the molded body obtained by the manufacturing method according to claim 6.
A first surface, a second surface facing the first surface, a third surface and a fourth surface intersecting the first surface and the second surface, and facing each other, the first surface, the first surface A porous sintered body having two surfaces, a fifth surface and a sixth surface that intersect with the third surface and the fourth surface and face each other;
An anode wire, a part of which is embedded in the porous sintered body, and the rest of which extends from the first surface,
A dielectric layer formed on the porous sintered body,
A solid electrolyte layer formed on the dielectric layer;
A cathode layer formed on the solid electrolyte layer, and comprising a capacitor element,
At least one of the fifth surface and the sixth surface includes a boundary line extending in a direction intersecting the longitudinal direction of the anode wire,
The boundary line defines an upper mold part that defines a region on the first surface side of the fifth surface or the sixth surface, and a region on the second surface side of the fifth surface or the sixth surface. And, due to the boundary between the upper mold part and the lower mold part that can slide independently of the upper mold part,
When viewed from the normal direction of the fifth surface or the sixth surface, the shortest length La in the longitudinal direction from the boundary line to the first surface and the length from the boundary line to the second surface The shortest length Lb in the direction is an electrolytic capacitor that satisfies the relationship of La≦Lb.
A first surface, a second surface facing the first surface, a third surface and a fourth surface intersecting the first surface and the second surface, and facing each other, the first surface, the first surface A porous sintered body having two surfaces, a fifth surface and a sixth surface that intersect with the third surface and the fourth surface and face each other;
An anode wire, a part of which is embedded in the porous sintered body, and the rest of which extends from the first surface,
A dielectric layer formed on the porous sintered body,
A solid electrolyte layer formed on the dielectric layer;
A cathode layer formed on the solid electrolyte layer, and comprising a capacitor element,
At least one of the fifth surface and the sixth surface includes a boundary line extending in a direction intersecting the longitudinal direction of the anode wire,
The boundary line defines an upper mold part that defines a region on the first surface side of the fifth surface or the sixth surface, and a region on the second surface side of the fifth surface or the sixth surface. And, due to the boundary between the upper mold part and the lower mold part that can slide independently of the upper mold part,
When viewed from the normal direction of the fifth surface or the sixth surface, the end portion of the anode wire embedded in the porous sintered body is located at the second position from the boundary line of the porous sintered body. An electrolytic capacitor that extends to the surface.